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Scientists See Promise for People and Nature in ‘Peak Farmland’

As agricultural production becomes more concentrated, growth in acreage devoted to food production has dropped far below projections, according to authors of a new paper. The graph shows how much land conversion has been avoided through this trend.Credit Population and Development Review

Now he’s alerted me to a new study and related lecture on what he and his co-authors are calling “peak farmland” — an impending stabilization of the amount of land required for food as humanity’s growth spurt plays out. While laying out several important wild cards (expanded farming of biofuels among them), Ausubel and his co-authors see a reasonable prospect for conserving, and restoring, forests and other stressed terrestrial ecosystems even as humanity exerts an ever greater influence on the planet.

Drawing on a host of data sets, the authors conclude that a combination of slowing population growth, moderated demand for land-intensive food (meat, for instance) and more efficient farming methods have resulted in a substantial “decoupling” of acreage and human appetites.

Here’s the optimistic opener:

Expecting that more and richer people will demand more from the land, cultivating wider fields, logging more forests, and pressing nature, comes naturally. The past half-century of disciplined and dematerializing demand and more intense and efficient land use encourage a rational hope that humanity’s pressure will not overwhelm nature.

Ausubel will describe the findings in a talk during a daylong symposium at his university on Tuesday honoring Paul Demeny, who at age 80 is stepping down as editor of the journal.

Ausubel’s prepared remarks are online. In his talk, he explains that while the common perception is that meeting humanity’s food needs is the task of farmers, there are many other players, including those of us who can choose what to eat and how many children to have:

[T]he main actors are parents changing population, workers changing affluence, consumers changing the diet (more or less calories, more or less meat) and also the portion of crops entering the food supply (corn can fuel people or cars), and farmers changing the crop production per hectare of cropland (yield).

Here’s an excerpt from the paper’s conclusion, which notes the many wild cards that make the peak farmland scenario still only a plausible, and hardly inevitable, future:

[W]ild cards remain part of the game, both for and against land sparing. As discussed, the wild card of biofuels confounded expectations for the past 15 years. Most wild cards probably will continue to come from consumers. Will people choose to eat much more meat? If so, will it be beef, which requires more land than poultry and fish, which require less? Will people become vegetarian or even vegan? But if they become vegan, will they also choose clothing made from linen, hemp, and cotton, which require hectares? Will the average human continue to grow taller and thus require more calories? Will norms of beauty accept obesity and thus high average calories per capita? Will a global population with a median age of 40 eat less than one with a median age of 28? Will radical innovations in food production move humanity closer to landless agriculture (Ausubel 2010)? Will hunger or international investment encourage cropland expansion in Africa and South America? (Cropland may, of course, shrink in some countries while expanding in others as the global sum declines.) And will time moderate the disparities cloaked within global averages, in particular disparities of hunger and excess among regions and individuals?

Allowing for wild cards, we believe that projecting conservative values for population, affluence, consumers, and technology shows humanity peaking in the use of farmland. Over the next 50 years, the prospect is that humanity is likely to release at least 146 mHa [146 million hectares, or 563,710 square miles], one and a half times the size of Egypt, two and a half times that of France, or ten Iowas, and possibly multiples of this amount.

Notwithstanding the biofuels case, the trends of the past 15 years largely resemble those for the past 50 and 150. We see no evidence of exhaustion of the factors that allow the peaking of cropland and the subsequent restoration of nature.

In an e-mail exchange today, I asked Ausubel about another issue touched on in the paper:

Looking around the planet, it’s clear from a biodiversity standpoint that all forests — or farming pressures — are not equal. For instance, in Southeast Asia, palm oil and orangutans are having a particularly hard time co-existing. So while the overall trend is great, do you see the need for maintaining a focus on particular “hot spots,” to use a term familiar in environmental circles?

So far, I don’t see lots of evidence that conservation campaigners (you are one on ocean resources) have found a way to accept this kind of good news and/or incorporate it in their prescriptions for sustaining a rich and variegated biological sheath on Earth. If you agree, any idea why?

His answer:

Indonesia is the number one place where letting the underlying trend work will not work fast enough. The list of threatened regions is quite well identified: parts of the central African forest, parts of the Amazon.

Some conservation groups have realized that the slow growth in demand for calories as well as pulp and paper are creating big chances to reserve or protect more land. In the right places, where crops are no longer profitable, some amounts of money can acquire large amounts of land for nature.

Conservation groups also ought to attend more to the ecological disaster called biofuels.

I encourage you to dig in on this paper and related work, which provides a useful guide for softening the human impact on a crowding planet. There’ll be plenty of losses, and surprises, but there are real prospects for sustaining a thriving, and peopled, orb.

6:57 p.m. | Addendum | For relevant work with somewhat different conclusions review the presentations from “Intensifying agriculture within planetary boundaries,” a session at the Planet Under Pressure conference in London last March. I’ll be adding links to other relevant analysis here.

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By 2050 or so, the human population is expected to pass nine billion. Those billions will be seeking food, water and other resources on a planet where humans are already shaping climate and the web of life. Dot Earth was created by Andrew Revkin in October 2007 -- in part with support from a John Simon Guggenheim Fellowship -- to explore ways to balance human needs and the planet's limits.